With Gaza in turmoil, ongoing violence in Syria, and Iraq battling an Islamist insurgency, news of Lebanon’s political gridlock understandably has fallen off the front page. But on Wednesday, Lebanese lawmakers failed to select a president for the eighth time. As part of Lebanon’s complicated balancing act among its many sectarian groups, the president must be a Maronite Christian — a requirement that isn’t so uncommon.

According to a recent analysis from the Pew Research Center, 30 nations require their heads of state to subscribe to a certain religion. Of those 30 countries, 17 require a Muslim leader, two a Christian, and two a Buddhist. One, Indonesia, must be led by someone who believes in Pancasila, the country’s founding ideology, which includes the belief in God. Eight nations forbid clergy members from ruling the land.

This interactive map details each nation’s requirement. Hover over each country to view details.

Pew put another 19 in a different category because those countries are monarchies. They too require their regents to practice a certain religion. That figure is somewhat inflated, however, as 16 are members of the Commonwealth of Nations and as such consider their head of state to be Queen Elizabeth II, nominal leader of the Anglican Church. Her many titles include "Defender of the Faith," which accords her a special role in the church. The other three — Sweden, Denmark, and Norway — must be led by followers of particular Christian denominations.

Pancasila — Indonesia’s guiding philosophy that its leader must believe in — is underpinned by five principles, including beliefs on society, religion, and government.

Back in Lebanon, governmental roles are split among various religious sects. Lebanon’s top leader, the president, must be a Maronite Christian. Its head of government, the prime minister, has to be a Sunni Muslim. In addition to these positions, the speaker of the National Assembly must be a Shiite Muslim, the deputy speaker of the parliament and the deputy prime minister must be Greek Orthodox, and the chief of the general staff must be Druze. Finally, seats in parliament must be divided half and half between Christians and Muslims.*

The rest of the world either doesn’t have religious requirements or outlaws any religious test for political candidates.

Correction, July 25, 2014: The seats in Lebanon’s National Assembly are divided half and half between Christians and Muslims. An earlier version of this article incorrectly stated that the seats were divided in a 6-to-5 ratio between Christians and Muslims. This was the previous ratio that was in effect until 1990. (Return to reading.)